Vacuum Distillation-Treated Spent Potlining as an Alternative Fuel for Metallurgical Furnaces

Abstract

AbstractSpent potlining (SPL) is a well-known hazardous waste from primary aluminum production, and recycling it as an alternative fuel for metallurgical furnaces is a promising application. However, because of the presence of volatile fluorides and fluoride compounds, there are significant environmental concerns and practical/engineering issues. An environmentally friendly technique involving pretreatment of SPL first cut at 700°C by vacuum distillation (VDM) is proposed herein. Using this process route, volatile and leachable fluorides (NaF, LiF, and Na3AlF6) in SPL first cut samples were successfully recycled. The distillation process was found to be beneficial for improving the fixed carbon content of the samples, and the combustion characteristics of the VDM residue were superior to those of raw untreated SPL. Such VDM residue could potentially be used in metallurgical furnaces and burners, with promising applications such as partial or full replacement of coal in pulverized coal injection (PCI) systems.\n